There are some descriptions about the background art of this technical field in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2005-526239 (Patent Literature 1). This publication says, “A mechanism that detects the intensity value of a beam with a comparatively large dynamic range which is emitted from a specimen such as a semiconductor wafer (a beam of scattered light, a beam of reflected light, or a beam of secondary electrons, for example) is provided” (Refer to “Abstract”).
In addition, Patent Literature 2 says, “A voltage adjustment device supplying DC voltages to plural elements, comprising: a first supply circuit that supplies a first voltage to the high potential terminals of the elements; and a second supply circuit that supplies plural voltages, which are lower than the first voltage, to the low potential terminals of the elements respectively, in which each of the plural voltages is dependent on the characteristic of the relevant element.”